The obel ( - or ÷ ) is an ancient graphic sign found in Greek texts and was used as a "foot call", something similar to the current asterisk ( * ), or as a correction mark for a possible error. It was supposedly created by Aristarco de Samotracia to point out Homer's texts that were suspicious to him. Today "÷" has use in mathematics to indicate "arithmetic progression" and sometimes as "mathematical division". See oelo , by etymology see obelisk .